The toy building sets of the above type are generally packed in cartons containing a predetermined number of bricks. The simplest bricks typically have a prismatic profile with a square or rectangular contour and, although they may differ from one another for size and shape, they have the common feature of being provided with projections on one base, which are shaped to fit into corresponding recesses formed on one opposite base. Alternatively, certain bricks may have only one base provided with projections or recesses.
None of the known toy building sets have bricks which can be both stacked on top of each other and linked side by side and at right angles. This deficiency considerably affects the versatility of the toy and the creative possibilities that the toy offers.
The toy building sets have evolved over the years, with the production of a variety of assorted bricks having more and more complex shapes specifically intended for creating predetermined profiles. Consequently, such bricks have a limited polyvalence and high manufacturing costs due to their complexity and to the high variety of different shapes.